EXPERIMENTAL Ejection charge test

[Rocket_Man]

I just built a new model and am wanting to test the ejection charges to make sure they will blow the nose cone. The model has a 2 cluster of 13mm A10-3T engines (tiny).


So I was going to go into the garage, grasp the plane in my hand, and test fire it. Since the engines are so small I am expecting just a little tug from the engines, really no big deal.

Has anyone tried this? These tiny engines cant put out that must thrust, its not like I am using D engines or anything. I know the fire risks and all that, I am just wanting to know the amount of "pull" when the engines ignite.

I am really looking for a second opinion from someone who will say ya its cool, tiny engines no big deal.

 

[troj]

Holding it in your hand is a bad idea. Think of the ramifications of it getting loose.

If you can rig up a jig that will hold it securely, and in a position where there's no fire risk created, then a static fire is reasonable.

-Kevin

 

[doug_kosty]

And you might be astonished at the quantity of smoke created. Even if it weren't a fire hazard to ignite the motor indoors, you would be much better off in open air. If you are in a densely populated area, might want to check that the downwind neighbors' windows aren't open as well.

 

[Scott Evil]

I am really looking for a second opinion from someone who will say ya its cool, tiny engines no big deal.

Probably not going to get that.:wink:

Can't really justify propellant use indoors unless you're in a Ratheon lab complex or something.

It might make some tactile sense to "Feel" the thrust of LPR motors but if something goes wrong it'll happen faster then you can react.

Most important, let's not make news in the local newspaper 'cuz' we screwed up.

 

[Evo666]

I can tell you when i was younger(15yo) I use to hold the rocket by hand and ignite them using motors from A to C. Yes its a slight tug at first. I also use to stick them into 2 litter bottles and launch them. If you ever saw a kid doing such thing at the Kingdome parking lot then it was possibly me.

The safer thing to do is strap the rocket to a table or something sturdy and non-flammable .

 

[jim fustini]

https://www.nar.org/SandT/pdf/Estes/qtrA3.pdf Why not this?

 

[Handeman]

https://www.nar.org/SandT/pdf/Estes/qtrA3.pdf Why not this?

Because it doesn't list the amount of powder used for the ejection charge, which is what his question is about.

If he knew that amount, he could just ground test it and the whole conversation about holding a lit motor would be irrelevant.

 

[sugardaddy]

One of the biggest problems i see from holding a rocket in your hand is the risk of the motor catoing. If that were to happen your face is going to be very close to it and that wont be pretty.

Danny

 

[Bill P]

So many scenarios going through my head. Not pretty.

Build a test stand of some sort and keep the safety table distance clearance or have proper shielding.

 

[Scott Evil]

Would be pretty easy to auger a rocket sized hole through a piece of wood and clamp it in a vise or something.

 

[jim fustini]

Handeman Then. Why did he post?


I am just wanting to know the amount of "pull" when the engines ignite.

.[/QUOTE]

 

[Wingarcher]

I looked up the thrust curve for an estes A10-3 and the peak is 12.64 N as stated on the certification document. Google converts that into 2.84 lbs force, so if you've got two going at once, 5.6ish lbs force. That's only a very very brief spike.

Test fire it (maybe strap it down to something instead of hold it).

Get video.

N

 

[GregGleason]

Here are two reasons why you shouldn't hold rockets in your hands:


NH002_2011-03-12_028 by D.Laney, on Flickr


TH002_2011-03-12_115 by D.Laney, on Flickr

Greg

 

[Highpowerrocketyahoo]

We are not seriously having this conversation are we? I mean really....

 

[[POW]Eagle159]

Well as long as you make sure the nose cone is loose enough than there should be no troubles.
OR what you could do is to stick an air compressor end and shoot a little air in the end of the rocket. this is like a perfect substitute for testing ejection charges. AND you don't have to use engines.